The present application relates to an airbag arrangement for a vehicle occupant restraint system. The airbag arrangement includes an airbag arranged on a side of a backrest of a vehicle seat in such a way that when inflated the airbag extends substantially vertically along the backrest and forward in a direction of travel of the vehicle. The airbag may be divided into separate inflatable chambers, each of which is assigned to different body regions of a vehicle occupant, for example the head and the thorax. The chambers are configured to support the vehicle occupant in the event of a side collision of the vehicle. The airbag arrangement may be used as part of a vehicle occupant restraint system and arranged to be folded up laterally in or on the backrest in a normal non-activated state. The airbag arrangement is inflated in the event of a collision of the vehicle and unfolded. The airbag arrangement then extends in an unfolded state to a side of the vehicle seat to intercept and support a lateral movement of the vehicle occupant as a result of the collision.